There are a wide variety of different equipment types employed in agriculture for the purpose of tilling soil. One type of a frequently used machine comprises a frame with its own running gear, suitable for covering a wide working range, which frame is towed across the field by means of a tractor. Such tillage implements may be designed, for instance, with soil loosening tools and/or cutting equipment, provided for instance in the form of so-called short disk harrows or spike tooth harrows or the like. Tillage implements of this sort may additionally be outfitted with sowing combinations and/or fertilizer spreader devices.
For transport purposes, parts of the frame may be pivoted about a horizontal longitudinal axis, for instance, in order to reduce the machine width to dimensions that comply with road traffic regulations. Such towed agricultural tillage or sowing implements with integrated soil packer elements require different types of the existing running gear variants, which are necessary for different driving purposes, such as for road traffic or, to some extent, for turning procedures in a field. Some implement types have a soil packer element, for instance, which is designed to be simultaneously used as an element of the running gear. This type of packer element is commonly provided with tires, which are equally suitable for driving in the field as well as on the road.
Insofar as the packer elements are, however, made from steel or other materials that are not suited for road traffic, it is necessary to have an additional running gear, which usually comprises a wheel axle with a lifting device to change the implement from a working position to a transport position and vice versa. Running gears and soil packers of this kind may be arranged in many different ways within the implement combination. The running gears may be disposed in the middle or at the end of the implement, in front of or behind the soil packers, for instance. The running gears and the soil packers are commonly functionally separated from each other and therefore each require their own frame components and lifting devices. These customary types of arrangement and construction require high technical input and also a relatively large amount of installation space. In the prior art, towed agricultural implements with their own separate running gears and soil packer elements are commonly constructed by lining up the different elements one after the other. By this structure and by the installation space that the running gears, or also the soil packer elements, require for vertical movement, for instance, such towed agricultural implements tend to be very long in terms of their longitudinal extension.
At the same time, the equipment that is used in agriculture is becoming perpetually larger and heavier, thus increasing the input needed for ensuring the stability of the framework structure, for instance, of such long and heavy implements. Furthermore, the longer and bulkier such implements become, the more difficult and unsteady will it be to drive them in comparison to shorter and smaller equipment. To prevent the increasing risk of such implements tilting sideways in road traffic is a challenge that has to be met.
WO 2005/015974 A2 discloses a towed agricultural tillage machine comprising a height adjustable running gear with a lifting mechanism involving rear support wheels, which can be pivoted downward from a raised rest position and into an operating position for supporting the implement in road traffic. In a separate operation, it is possible to pivot disk-shaped tillage tools together with their support frame elements upward from a lowered operating position, which is used for driving on the field, into a rest position of the tillage tools for the purpose of driving on the road with the implement. The mechanisms for pivoting the support wheels and the tillage tools can be actuated separately from each other.
U.S. Pat. No. 7,073,604 B1 discloses a towed agricultural tillage machine with a very wide working range and comprising a multitude of height adjustable front support wheels and two pairs of height adjustable rear support wheels. A support frame of the machine comprises several sections that are articulately joined to each other so that they can pivot in relation to each other to adjust to different ground profiles during driving. Arranged immediately in front of the rear support wheels are disk-shaped packer wheels extending across the entire working range of the tillage machine.
DE 199 08 241 A1 deals with a towed agricultural implement combination that has several tillage devices in the form of disk harrow elements arranged on a frame. A running gear with running wheels is mounted at the rear end of the frame on pivotal supports. The supports are pivotal about a horizontal transverse axis and hinged to a cross beam of the frame. The pivot supports can be lowered and lifted together with the support wheels by means of double acting hydraulic cylinders. In order to adjust the implement combination to a transport position, the running gear and the ground roller are first lifted before securing elements are deactivated. It is then possible to lower the pivot supports with the running wheels, thus converting the implement combination to a transport position. The process of converting the implement from a transport position with an activated running gear to a working position with a raised running gear and vice versa requires a high level of constructional input on the one hand side, while, on the other hand, the conversion between the two operational modes can still not be effected in a fully automated manner.
WO 97/40660 A discloses another towed agricultural tillage machine comprising several disk harrow elements, subsequent packer rollers, and a rear end running gear. The packer rollers and the running gear wheels arranged behind the packer rollers in the direction of driving are located together on a rear carrier, which can be pivoted by means of an adjuster cylinder about a horizontal swivel axis disposed at the rear end on the machine frame. The rear carrier is pivoted upward on compressing the double acting hydraulic cylinder located above the swivel axis, causing the wheels to lose ground contact and leaving only the packer roller supported on the field ground. On extending the cylinder, in contrast, the rear end wheels are lowered downward and thereby lift the entire machine from the ground up to the point where all tillage tools lose the tangent contact with the ground and the machine is ready for road traffic. In this machine variant, the running gear and the packer unit form a largely rigidly connected constructional unit, which can only be pivoted on a lever arm as a whole. The running gear wheels cannot be shifted in relation to the packer unit.